Restructuring - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017	Oct. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 2	$ 152	$ 14	$ 304
Current restructuring liability reported in Accrued restructuring	256		256		$ 445
Non-current restructuring liability reported in Other liabilities	70		70		96
All Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges			14
Current restructuring liability reported in Accrued restructuring	$ 31		$ 31		$ 158